Steam assisted gravity drainage (SAGD) involves two horizontal wells, one acting as an injector and the other as a producer. The producing well is located at the bottom of the formation and the injecting well is approximately 5 meters above. As bitumen becomes mobilized, force of gravity along the walls of a resulting steam chamber induces the flow of the bitumen into the producing well.
Although the SAGD process is currently commercially successful in some applications, many limitations restrict economic viability of the process. One area where traditional SAGD is limited is in thin bitumen reservoirs (e.g., less than 10 meters in thickness). Costs associated with such processes require sufficient reservoir thickness to make recovery of the oil economically viable.
In thinner reservoirs the steam chamber reaches the top of the reservoir very early in the production process. Once the steam chamber reaches the top of the reservoir it begins to lose heat to the overburden. This heat loss reduces the thermal efficiency of the process.
Therefore, a need exists for improved methods and systems for recovering of oil obtained from steam injection based operations.